Composition



Patented Apr. 21, 1931 UNITED STATES PATENT OFFICE WILLIAM HOWARDWRIGHT, F SCHENECTADY, NEW YORK,- ASSIGNOR TO SCENECTADY VABNISHCOMPANY, OF SCHENECTAIJY, NEW YORK, A CORPORA- TION OF NEW YORKCOMPOSITION No Drawing. 7

10 lating material, such as paper, vegetable or animal fabric, arcingfrequently results between difi'erent coils, due to corrosion of theinsulation, and difference in potential between'the coils. While the oilin which the transformers are immersed is a cooling and insulatingmedium, nevertheless, such oil has frequently been found to containmaterials rendering it conductive or to have had its chemicalconstitution so changed that it will allow an arc to jump from onetransformer coil to another. Where, as stated, the insulation about theconductors has decayed and there exists a difierence in potentialbetween the one or more ad'acent transformers, the oil may be of such caracter as topermit of arcing, and thus destroy the efficiency of thetransformers.

The difficulty heretofore has been to find a material which would not bedissolved by mineral oils in oil cooled transformers. As is well known,these transformers run at a considerable temperature rise, and it isessential that the insulation of the coils be 5 insoluble in the hotmineral oil. The proper cooling of the transformers depends on therapidity "of circulating of the oil in thetransformer tank surroundingthe coils. Where the insulation is soluble, the oil becomes heavy 40 andthe circulation of the oil impeded.

Hence the cooling of the coils is not as efficiently done as when theoil is thinner, and the temperature rise of the machine consequentlyhigher and its electrical capacity lower.

sist in maintaining the conductor always Applieation flled October 13,1927. Serial No. 228,035.

properly insulated so as to prevent the possibility of arcing. Y

A very important object of this invention is therefore the provision ofan oilproof coating composition which is not only insulating but whichis moreover insoluble in the hot or cold oil surrounding thetransformer.

this manner, the circulating efliciency of the oil is increased and noobjectionable chemical compounds are formed.

A further obj not of the invention is to provide a composition of thischaracter which may be prepared in liquid form, or prepared in liquidform, permitted to solidify and then subsequently rendered fluid forimpregnation and coating purposes.

The invention has, moreover, in mind the production of a plastic whichmay be suitably shaped or moulded and also rolled, and

.when cooled is a hard solid substance of nice appearance,non-conductive and waterproof.

The composition of the'present invention comprises preferably a resinsuch as rosin, colophony or abietic acid. I have found, however, thatresins containing gums, ethereal oils and other important constituentsmay be employed, and in fact any resinous material may be utilized inaccordance with requirements and the product desired.

With the resin, I preferably mix or combine a natural gum which is aspecies of Xanthorrhoea. One of such gums which I have used is accroidesor acaroids of which there is an abundant and cheap supply obtainablefrom Australia.

There are two kinds of gum accroides both characterized by being estersof paracoumaric acid.

Other species of Xanthorrhoea may be employed in accordance with theproduct desired, but I Will here set forth the red and yellowgum'accroides.

Red accroides comprises paracoumaric acid (C H O 1%; bcnzoic acid intraces and paracoumaric acid 2%, both in combination witherythrocsinotannol (C H Q OH) paraoxybenzaldehyde 15%. The bung-85%,consists of the erytllroresinotannol ester of paracoumaric acid. Theabsence of cinnemic acid distinguishes this resin from yellow acaroid.

The yellow acaroids comprise free paracoumaric acid (0 11 0 4%; freecinnamic acid .5%; combined paracoumaric acid 7% and combined cinnamicacid. 6%. Both acids form esters with xanthroresinotannol producingchiefly the corresponding ester of paracoumaric acid which forms themain constituent of this resin.

Also there are probably present styracin (0 E 0 cinnamic phenylpropylester, paraoxybenzaldehyde, and possibly vanillin.

To this mixture may be added vegetable, animal and mineral oils, orother resins, both natural and synthetic, for instance, the prod uctknown commercially as paracumaron. However, the resin and gum are thefundamental ingredients, and the other substances may or may not beadded, as desired.

The proportion of the ingredients is determined by the melting point ofthe finished compound desired. This melting point varies for mostpurposes from 100 C. to 150 C. in accordance with the particular type ofcoil or conductor to be treated.

The difference in the melting points may be easily obtained by using agreater or less amount of each ingredient in the mixture, it being foundthat a composition consisting of equal parts of the two materials willsuliice for a large number of cases.

It has been found useful in some instances to add to the mixture othermaterials for instance, castor oil or fatty acids in the nature ofstearic acid and other resins of both natural and synthetic character.These substances may be added singly to a mixture of rosin and gumaccroides or in some cases both stearic acid and castor oil may be used,or these two ingredients together with other resins may be employed.Also either stearic acid or castor oil may be employed in conjunctionwith such other resins in accordance with requirements of a particularcase.

The castor oil and other oils for instance, serve to reduce thebrittleness of the resin and accroides composition, while stearic acidacts in some cases as a flux to give a better combination of the twomain ingredients with or withoutthe castor oil or other resins.

The use of resins natural or synthetic, for example, paracumaron, isuseful at times for varying the melting point of the i'OIHPOSltion andfor determining its solubility in connection with various types oftransformer oils.

For example the mixture may comprise:

Rosin, gum accroides, castor oil.

Rosin, gum accroides, stearic acid.

Rosin, gum accroides, castor oil, stearic acid.

Rosin, gum accroides, resins (natural or synthetic) Rosin, gumaccroides, stearic acid, resins (natural or synthetic).

Rosin, gum accroides, castor oil, resins (natural or synthetic).

Rosin, gum accroides, stearic acid, castor oil, resins (natural orsynthetic).

As previously stated, for a great number of instances, a plain mixtureof gum accroides and rosin in equal parts will suilice and theproportions of these constituents may be varied to change the meltingpoint. The melting point may be changed for example by adding a greateror smaller amount of rosin.

Where a single one of the ingredients above noted is employed, they maycomprise up to approximately ten per cent (10 of the mixture.

For instance, in the use of castor oil or resins ten per cent (10%) ofthe mixture has been found suliicient. In the case of stearic acid, theamount found necessary for the best result is approximately five percent- (5%). \Vhere the ingredients are employed together, their totalproportion should be substantially ten per cent (10%) of the mixture.

Of course, a quantity more or less may be useful in accordance with thecharacter of rosin, and the nature of the gum, and the percentage ofproportions here recited are those.which have been found experimentallyand practically satisfactory with a wide.

range of ingredients and applications.

In preparing my improved oil-proof and waterproof composition, the gumaccroides and rosin together with the addition ingredients, if employed,may be melted together or separately, and mixed in flue-d condition tothe proper consistency, and the fluid strained and permitted to coolinto a hard solid compound having a melting point from 100 C. to 150 C.,more or less. By having the product in solid form, it may be easilytransported and employed as desired.

In treating transformer coils or for other impregnation purposes, aseries of tanks of suitable size are employed. In one of the tanks, thecomposition of the present invention is placed and melted to a fluidcondition, say at a temperature of approximately 325 F. The other tankreceives the coils and is preferably provided with means for exhaustingair therefrom, being in the nature of a closed container.- After the airhas been exhausted, the coil contained in the chamber is heated to expelany moisture. Thereafter, the melted material in the other tank ispassed into the chamber containing the article to be treated, and thearticle immersed in the treating substance.

Pressure is then applied in the closed chamber containing the coil orother article great variety of applications where a grease-.

immersed in the composition of my invention, and such pressure ismaintained for a sufficient time to force the compound into thedi-electric covering of the coils or article to be impregnated. Thereresults a hard coating thoroughly oilproof and insoluble in the hot orcold oil surrounding the transformer.

As previously stated, the ingredients of 0 my composition are preferablymelted together until the proper consistency or degree of plasticity isreached, such that a uniform product may be obtained, and thereafterpermitted to cool int-o solid form.

This is the finished article which is utilized in the impregnatingprocess just described. My invention is obviously useful for a proof orwaterproof impregnation compound is desirable. For example, theingredients herein recited may be dissolved in alcohol, petroleum,naphtha, menthanol and a variety of other solvents, or two or more ofthese solvents may be used together.

This solution so obtained may be applied to asurface to be treated bymeans of spraying, brushing, dipping or other mechanical process, and ithas been found under such circumstances that a hard insolubleimpregnation and protective coating is produced.

It will be understood, of course. that a great variety of vegetables,animal and mineral oils other than castor oil may be used as theaddition ingredients of my invention, as well as resins of varioustypes, both natural and synthetic.

In referring to the use of paraclnnaron, it will be understood that Ihave in mind a resin having this commercial trade name. or a resinhaving the formula C H O. I also have in mind the use of commercialcumaron which is a mixture of paracumaron and para indene. Thesematerials may be used in combination with a resin or with fatty acidssuch as castor oil and stearic acid, as previously described. It Will beunderstood, however, that the composition so obtained is not the fullequivalent of the natural gum accroides and resin, although it may beused for the same purpose. I have also found that paracumaric acidcombined with a resin has excellent oil proofing qualities, but theresults are not as good as a composition of rosin and gum accroides, asdescribed.

My composition is a non-conductor. and in some cases may be employedsolely as the insulating material or impregnating agent.

In other cases, as for example, electrical applieations, it may be usedto impregnate the di-electric or insulator and to afford not only agreater insulation, but a protection to the first coating, which willprevent its decay or corrosion, due to the action of either theatmosphere or as in the case of transformer coils, the action of the oilin which such coils are usually immersed, tending to dissolve it. Itmust, morover, be understood, that since 'I obtain a solid product, thisproduct is available in its solid form for a great variety of purposeswhere an insulating or waterproof material is desirable, and the solidproduct may be shaped, if preferred, and sawed or cut to any desiredform, for example, while the composition is cooling after a propermixture is obtained, such cooling may be accomplished in a suitablemold, or the material may be rolled into sheets. The present inventionis not limited, therefore, to a coating or impregnating compound,although the composition is especially useful in this connection, since,obviously, it may be used in its solid form for an innumerable number ofpurposes, meeting requirements for which it is characteristicallyuseful.

It will be understood that in some cases the materials may be placed ina tank adjacent to the article to be treated, and there and thenpropelled or transported to the treating chamber. This step would bedesirable in some operations, and would eliminate the necessity ofawaiting the cooling of the mi Xturc to solid form.

In making a plastic composition, which can be rolled into sheets and cutto suitable sizes and shapes or moulded to various shapes, it may bedesirable to add a hardening agent, and for this purpose any well knownmaterial may be used. Of course, heat and pressure either together orseparately may be employed, depending, of course, upon the nature of thecomposition.

I claim:

1. In the art of treating electrical coils having a covering and adaptedto be immersed in a cooling medium such as oil, the step which comprisesimpregnating the coverin of such coils with a composition insoluble inthe oil comprising an accaroid resin.

2. In the art of treating electrical coils having a covering and adaptedto be immersed in a cooling medium such as oil, the step which comprisesimpregnating and coating the covering with a composition insoluble inthe oil comprising an accaroid resin, the said composition forming ahard coating about the coils.

3. In the art of treating electrical coils having a covering and adaptedto be immersed in a cooling medium such as oil, the step which comprisesimpregnating the covering with a composition insoluble in the oilcomprising an accaroid resin and a pure resin.

4. In the art of treating electrical coils having a covering and adaptedto be immersed in a cooling medium such as oil, the step which comprisesimpregnating and coating such covering with a composition insoluble inthe oil comprising an accaroid resin melted and mixed to the desiredconsistency, 7

and a pure resin, the said composition forming a hard coating about thecoils.

5. In the art of treating electrical coils having a covering and adaptedto be immersed in a cooling medium such as oil, the step which.comprises impregnating such covering with an insulating compositioninsoluble in oil comprising an accaroid resin, rosin and one or moreagents in the nature of castor oil, stearic acid, and another resin.

6. In the art of treating electrical coils having a covering and adaptedto be immersed in a cooling medium such as oil, the step which comprisesimpregnating and coating such covering with an insulating compositioninsoluble in the oil comprising an accaroid resin, rosin and one or moreaddition agents in the nature of castor oil, stearic acid andanotherresin, the said composition forming a hard coating about thecoils.

7. In the art of treating electrical coils having a covering and adaptedto be immersed in a cooling medium such as oil, the step which comprisescovering such coils with an insulating composition comprising anaccaroid resin and a plasticizer.

8. In the art of treating electrical coils having a covering and adaptedto be immersed in a cooling medium such as oil, the step which comprisescovering such coils with an insulating" composition comprising anaccaroid resin, rosin and a plasticizer.

9. In the art of treating electrical coils having a covering and adaptedto be immersed in a cooling medium such as oil, the step which comprisescoating such coils with an insulating composition comprising an accaroidresin, rosin and a plasticizer and flux.

10. An electrical coil impregnated and coated with an oil proof andwater proof composition comprising an accaroid resin and forming aninsoluble coating about the coil.

In testimony whereof I have hereunto set my hand.

WILLIAM H. WRIGHT.

